The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Known audiovisual teaching devices for teaching music comprise a board containing multiple musical staves. A series of wires or low resistance metallic strips represent the lines and spaces of the musical staves and are arranged to conduct current pulses of relatively high amplitude. The devices further comprise a handheld “wand” which includes an inductor and is connected to the board via a cable. When the wand makes contact with or adjacent one of the wires of the musical stave this closes a circuit that drives an integrated loudspeaker system.
There are a number of disadvantages with these known devices. Firstly, the wand needs to be tethered to the music board using a heavy duty screened cable. Moreover, the orientation of the inductor does not allow accurate sensing of the wires/metallic strips. This can cause errors in establishing which wires/metallic strips of the musical stave have been detected. Also, the mechanical orientation and fixing of the wires/metallic strips is difficult to achieve. Finally, the use of high current, high frequency pulses with a fast rising edge generates large amounts of radio frequency interference, thus making EMC compliance difficult to achieve.